This proposed research is an Ancillary Study to the NIH supported Beta Blocker Heart Attack Trial. The objectives of the present study are to determine the character of blood flow in minute vessles following myocardial infarction and to determine the extent to which propanolol, administered as long term therapy, influences small blood vessel hemodynamics. To accomplish this, blood flow is measured in the bulbar conjunctival vessels of patients half of which will receive propanolol and half of which will receive a placebo. The Trial is "Double Blind". Velocity in the microvessels will be determined by first videotaping the flowing blood using video processing and cross-correlation techniques will be applied. The result of this analysis will produce blood velocity data in both arterioles and venules in each patient. The patient population will be approximately 144. All patients will be followed for at least a period of 2 years (some 4 years) at 6 month intervals. Velocity data will be obtained in the same vessels at each visit. The composite data obtained in this study should allow for determination regarding the effects of both time, (placebo group) and propanolol on small vessel hemodynamics following myocardial infarction.